FIG. 22 shows a structure of a conventional microwave heating apparatus including a vapor generator.
A main body 1 of the microwave heating apparatus (hereinafter, referred to simply as the "main body 1") includes a heating chamber 3 for accommodating an item 2 to be heated (hereinafter, referred to simply as the "item 2"), a magnetron 4 provided outside the heating chamber 3, and a vapor generator 5 for generating vapor 10 to be supplied to the heating chamber 3. The vapor generator 5 includes a vapor generating chamber 6 and a water supply tank 7 in communication with the vapor generating chamber 6.
The item 2 is heated for cooking by microwaves 8 generated by the magnetron 4 and the vapor 10 supplied to the heating chamber 3 from the vapor generating chamber 6. The vapor generating chamber 6 generates heat by an electric current induced by an induction heating coil 9 and thus generates the vapor 10.
By heating the item 2 using both the microwaves 8 and the vapor 10, the moisture is maintained in the item 2 more than in the case where only the microwaves 8 is used for heating. Moreover, the vapor 10 heats the item 2 uniformly and thus more satisfactorily.
However, the conventional microwave heating apparatus has the following problems.
The microwave heating apparatus requires 2 to 4 minutes to start up, i.e., from the time the induction heating coil 9 is activated until the vapor 10 is generated, as shown in FIG. 23. This prolongs the cooking time. For 1 to 2 minutes after the induction heating coil 9 is deactivated, the vapor 10 is still being supplied to the heating chamber 3. This can cause some danger when taking the cooked item 2 out from the heating chamber 3.
Furthermore, when the vapor 10 is supplied to the heating chamber 3, the vapor 10 contacts the walls of the heating chamber 3 and thus generates dew condensation. The microwaves 8 are absorbed by the dew condensation, thereby causing non-uniformity in the electric wave distribution in the heating chamber 3. Thus, uniform heating by the microwaves 8 is not realized.
The dew condensation also tends to de-sanitize the heating chamber 3.
The present invention has an objective of providing a microwave heating apparatus for heating and cooking an item by reducing the dew condensation in a heating chamber.
The present invention has another objective of providing a microwave heating apparatus for heating and cooking an item, which supplies high-speed vapor corresponding to the microwaves so as to realize quicker cooking, more safety in removing the cooked item with no vapor remaining in the heating chamber, and a reduction in dew condensation in the heating chamber.